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Message-Id: <20120309190205.565991711@linuxfoundation.org>
Date:	Fri, 09 Mar 2012 11:02:42 -0800
From:	Greg KH <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Alexandre Bounine <alexandre.bounine@....com>,
	Chul Kim <chul.kim@....com>,
	Matt Porter <mporter@...nel.crashing.org>
Subject: [ 40/95] rapidio/tsi721: fix queue wrapping bug in inbound doorbell handler
3.2-stable review patch.  If anyone has any objections, please let me know.
------------------
From: Alexandre Bounine <alexandre.bounine@....com>
commit b24823e61bfd93d0e72088e4f5245287582ed289 upstream.
Fix a bug that causes a kernel panic when the number of received doorbells
is larger than number of entries in the inbound doorbell queue (current
default value = 512).
Another possible indication for this bug is large number of spurious
doorbells reported by tsi721 driver after reaching the queue size maximum.
Signed-off-by: Alexandre Bounine <alexandre.bounine@....com>
Cc: Chul Kim <chul.kim@....com>
Cc: Matt Porter <mporter@...nel.crashing.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/rapidio/devices/tsi721.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -410,13 +410,14 @@ static void tsi721_db_dpc(struct work_st
 	 */
 	mport = priv->mport;
 
-	wr_ptr = ioread32(priv->regs + TSI721_IDQ_WP(IDB_QUEUE));
-	rd_ptr = ioread32(priv->regs + TSI721_IDQ_RP(IDB_QUEUE));
+	wr_ptr = ioread32(priv->regs + TSI721_IDQ_WP(IDB_QUEUE)) % IDB_QSIZE;
+	rd_ptr = ioread32(priv->regs + TSI721_IDQ_RP(IDB_QUEUE)) % IDB_QSIZE;
 
 	while (wr_ptr != rd_ptr) {
 		idb_entry = (u64 *)(priv->idb_base +
 					(TSI721_IDB_ENTRY_SIZE * rd_ptr));
 		rd_ptr++;
+		rd_ptr %= IDB_QSIZE;
 		idb.msg = *idb_entry;
 		*idb_entry = 0;
 
--
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